Rotary vibratory hammer



March 14, 1950 E.v CRAIG ROTARY vBRAToRY HAMMER 2 Sheets-Sheet l Filed July 11, 1945 .March 14, 195Qw E. CRAlG 2,500,402

ROTARY VIBRATORY HAMMER Filel July 1l, 1945 2 Sheets-Sheet 2 Im/entor.

Patented Mar. 14, QS

UNITED STATES PATENT OFFICE 2 Claims.

This invention relates to improvements in vibratory hammers capable of imparting sharp and rapid impact blows and the principal objects of the invention are to provide a hammer, particularly adapted for use in rock drilling, or rivetting, or for breaking up masses of solid material such as concrete, which may be operated ei'iectively by any suitable form of high speed rotary machine either directly or indirectly connected with the impact mechanism.

A further object is to devise a tool which will operate with the minimum of rebound, thereby enabling its continued use without excessive strain on the operator.

A still further object is to devise a simple and inexpensive construction of tool which will be extremely rugged and in which there will be the fewest possible number of parts and which may be easily and quickly taken apart and reassembled.

The principal feature of the invention consists in the novel construction and arrangement of a plurality of Weighted roller hammer members engaging a circular trackway and driven therearound to periodically engage a reciprocable member to impart successive impact shocks to the tool.

A further important feature consists in the novel means of driving the hammer rollers without transmitting rebound shocks back to the driving mechanism and the frame of the hammer.

A still further feature of importance consists in offsetting the reciprocable tool operating member relative to the axis of the rotatable hammer driving member so that the maximum impact effect may be produced with the minimum effect of rebound.

A still further feature consists in the novel manner of rotating the tool concurrently with the application of the impact shocks thereto.

In the accompanying drawings Figure 1 is a longitudinal mid-sectional view of my improved hammer taken transversely of the hammer driving member.

Figure 2 is a longitudinal sectional View of the hammer taken through the line 2 2 of Figure 1.

Figure 3 is a plan section taken on the line 33 of Figure l.

Figure 4 is a plan section taken on the line 4-4 of Figure 1.

Referring to the accompanying drawings, I is the lower tool-holding portion of the hammer structure which is of substantial cylindrical form having a lateral ilange 2 extending around the upper end thereof.

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Within the body I is an axially arranged cylindrical recess 3 extending downwardly from a shallow recess l in the top.

A cylindrical bushing 5 is rotatably mounted in the recess 3 and the squared shank 6 of the impact tool is arranged therein.

A spur gear l is secured to the tcp of the bushing 5 and operates within the shallow recess il and this spur gear meshes with a gear Il mounted on a vertical shaft 9.

Mounted on the flange 2 of the holder l is a correspondingly flanged member I0, which is secured by suitable bolts II and encloses the meshing gears l and 8.

A counterbored recess I 2 is arranged in the bottom portion of the flange member I0 in alignment with the cylindrical recess 3 and within this counterbored recess is housed a tappet member I3 which has an enlarged cylindrical porton Ill slidable in the counterbore with a reduced extension end I5 extending into the centre bore of the bushing 5 and engaging the shank end of the drill rod.

A coiled compression spring l5', mounted within the counterbored recess I2, engages the f cylindrical portion I4 of the tap-pet member.

A ring-shaped member IE, preferably forming part of the flanged member I0, is arranged in an oiset position at the upper end of said member I0 with its transverse axis oiset laterally from the axial line of the tool 6 and tappet I3, as shown particularly in Figure 1. This ring member is preferably in the form of a steel casting and the inter-peripheral surface of the ring is formed with a central groove Il which separates a pair of circular tracks i8 arranged at either side thereof.

Flanged discs I9 and 20 are secured respectively to the outer facesof the ring I0 and are provided with central bosses in which suitable ball-bearings 2I are arranged.

A rotatable member 22, having a pair of spaced apart circular flanges 23, is journalled in the b-earings 2l between the flanged discs I9 and 20. The flanges 23 are formed with diametrically opposite and radially disposed slots 2i and slidably mounted in these are the bearing blocks 25.

Roller hammer members 26, formed with trunnions 2l journalled in the blocks 25, are formed with the circular portions 28 arranged either side of the central striker surface 29 of the hammer, which is preferably formed with a transverse camber.

This central portion normally fits between the tracks I8 within the groove I'I, while the outer portions 28 engage the trackways.

There are preferably two of these rotatable hammer members arranged in diametrically pposte relation to each other and movable radially outwardly in the slots 2li, so that when the member 22 is rotated, centrifugal force carries the rotatable hammers outwardly so that their circular portions 28 maintain rolling Contact with the tracks E8.

The member '22 may be driven in any suitable manner. The shaft portion may be directly connected with the drive of an electric motor or other prime mover, or it may be suitably geared.

It will be seen that by the offset arrangement of the tappet i3 and its co-operating tool relative to the axis of the circular trackway on which the rotatable hammers roll, the said hammers in the downward compo-nent of their rotation strike the upper end of the tappet, which, being in contact with the tool G, imparts to the tool the impact shock or the hammers in their descending movement in the ring it.

It will be appreciated with reference to Figure lthat due to the fact that the reciprocal tapet or impact receiving member i3 reciprocates and extends into the trackway in a plane oiTset from the Vertical plane oi the axis of the member Z2, the reactive force imparted by the tappet to the rollers upon being struck by the rollers acts in a direction in angular relation to the radius oi the member Z2 whereby the rollers are caused to spin on their trunnions 2l simultaneously with their inward radial movement as permitted by the journal blocks 25 sliding in the slots 2li. With this arrangement a substantial portion of the reactive force oi the tappet is expended and converted into harmless spin energy in the rollers, reducing man terially the impact stresses and shock on the walls of the radial slots of the member 22 to lessen vibration and increase the life of the hammer and its eiiiciency of operation.

rShe natural rebound of the tool striking its object is cushioned, by the spring l5 against impart ing direct vibratory shocks baci; against the frame structure of the tool, but it will be seen that the rapidly rotating member 22, with its rotatable hammers being carried around the ring I3, imparts a very rapid succession of impact shocks to the tappet and the tool.

it is of course important that the operating tool 8 should be rotated and the gears 'i and 8, operatively connected with the vertical shaft 9, are rotated through the operation of a spiral gear 2S mounted on the shaft ci the member E2 and a spiral gear mounted on the shaft S. It w l be understood that the roller hammers i rounded or crowned peripheres being made or hardened steel will maintain their shape indennitely. Their rolling motion in Icontact with the tracks lli ensure their continual movement so that a different portion of the periphery will come into contact with the tool tappet at practically every blow.

lt will also be understood that immediately upon striking the tappet each hammer will be free to recede into 'the radial slot of the rotating driving element, and the hammers having no direct connection with the ring or any part of the :frame of the tool, will not impart rebounding vibrations.

This function is also Very materially assisted through the actuation of centrifugal force preventing the hammers being driven backward against any solid surface of the machine.

It will b-e understood that the hammers, the tappet and the trackway supporting the hammers may be made of materials highly resistant to wear and impact shocks, and particularly because of the rotative action of the hammers individually on their own axes the machine will operate for extremely long periods without the necessity of replacements for wear or breakage.

It will however be seen that all parts of the machine are readily accessible. The hammers and their driving elements are fully accessible by simply loosening the plate i9 and sliding it outward on the shaft. The tool-holding bush and tappet may be readily examined or altered by simply separating the lange member It from the member l.

The device is simple, inexpensive to construct. It operates at any desirable speed and imparts a succession of distinct hammer blows directly to the tool and it will be understood that it may be made in various sizes and weights and will be remarkably efficient.

In the operation of this tool it will be noted that the operator in applying pressure to the tool presses downwardly against the spring i5 so that the inward end of the tappet lil projects into the path of movement of the hammer and in accordance with the amount of compression of this spring the magnitude oi the impact blow ci the hammers will be regulated.

It will be noted also that the hammer in its downward movement strikes perpendicularly over the axis oi the tappet, thus imparting its full impact directly on the axis of the drill.

What I claim as my invention is:

1. A vibratory hammer comprising a casing formed with a circular trackway, a rotatable member journalled centrally of said trackway to rotate in the plane of said trackway, means for driving said rotatable member, at least one journal block slidably mounted in and guided `by sait rotatable member to slide radially thereof, a weighted hammer roller journalled in said block and engaging and rolling freely on said trackway upon rotation of said rotatable member, and an impact-receiving member slidably mounted in a bore in said casting to reciprocate in the plane of said trackway and located to extend into said trackway in a plane oiset from a vertical plane through the axis of rotation of said rotatable member whereby reactive force exerted by said impacoreceiving member upon being struck by said hammer roller acts in a direction to impart spin to said hammer roller simultaneously with the driving of said journal yblock and hammer roller radially inwardly to expend a substantial portion oi said reactive force as spin energy reducing reactive impact stresses on said rotatable member.

2, A vibratory hammer comprising a casting formed with a circular trackway, a shaft journalled transversely and axially of said trackway and formed with a pair of spaced-apart lateral extensions having paired radial slots, diametrically balanced weighted hammer rollers having circular peripheral surfaces engaging said trackway when rotated, said rollers formed with trunnions journalled for rotation in bearing blocks radially slidable in said radial slots, means for rotating said shaft, and an impact-receiving member slidably mounted in a bore in said casting to reciprocate in the plane of said trackway and located to extend into said trackway in oiiset relation to a vertical plane through the axis of said shaft to impart upon being struck by said hammer rollers a reactive force acting to spin said rollers simultaneously with driving said rollers and bearing Number blocks radially inwardly in said radial slots. 9.17,'731 ERNEST CRAIG. 1,887,980 2,094,184 REFERENCES CITED 5 2,259,307 The following references are of record in the le of this patent:

Number UNITED STATES PATENTS 294,331 Number Name Date 10 356588 606,139 Hartman June 21, 1898 Name Date Jackson Apr. 6, 1909 Martin Nov. 15, 1932 Noble Sept. 28, 1937 Edwards et al Oct. 21, 1941 FOREIGN PATENTS Country Date Great Britain July 26, 1928 Great Britain Sept. 10, 1931 

